US10753737B1ActiveUtility
Method and optical system for reconstructing surface of object
Est. expiryAug 27, 2039(~13.1 yrs left)· nominal 20-yr term from priority
G01B 11/2513G01B 11/2527G01B 11/2441G01B 11/24G01B 11/2518G01B 11/25
72
PatentIndex Score
1
Cited by
18
References
12
Claims
Abstract
A method for reconstructing a surface of an object includes the steps as follows. A light beam is modulated by a spatial light modulator (SLM) and is projected to form a pattern, wherein the pattern has a transmittance distribution in a cosine distribution such that the pattern is formed to become a fringe pattern with a periodic change. A first impulse and a second impulse present within a first period and a second period of the cosine distribution, wherein a position where the first impulse occurs within the first period and a position where the second impulse occurs within the second period are different. The light beam is guided to an object so as to form a scan pattern on the object. The scan pattern is read. According to the scan pattern, a surface profile of the object is calculated.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A method for reconstructing a surface of an object, comprising steps of:
modulating a light beam by a spatial light modulator (SLM), and the light beam being projected to form a pattern, wherein the pattern has a transmittance distribution in a cosine distribution such that the pattern is formed to become a fringe pattern with a periodic change, the transmittance distribution at least comprises a first impulse and a second impulse, and the first impulse and the second impulse respectively present within a first period and a second period of the cosine distribution, wherein a position where the first impulse occurs within the first period and a position where the second impulse occurs within the second period are different;
guiding the light beam to the object, such that a scan pattern is formed on the object;
reading the scan pattern; and
calculating a surface profile of the object according to the scan pattern.
2. The method of claim 1 , wherein the pattern is formed by a plurality of pixels aligned along a direction of a straight line, and the cosine distribution satisfies:
t
=
A
+
B
cos
[
2
π
x
T
0
+
2
π
m
M
δ
(
x
-
n
T
0
-
l
)
]
,
wherein t is the transmittance distribution of the fringe pattern, A and B are real numbers, x is a pixel order on the direction of the straight line, T 0 is a fringe period of the fringe pattern, and x. M, m, n and 1 are positive natural numbers, wherein m<M, 1<T 0 , and the positions where the first impulse and the second impulse occur within are defined by δ(x−nT 0 −l).
3. The method of claim 1 , wherein a peak value of the first impulse and a peak value of the second impulse are different.
4. The method of claim 1 , wherein the first period and the second period are two continuous periods of the cosine distribution.
5. The method of claim 1 , wherein the step of calculating the surface profile of the object comprises:
reconstructing the surface profile of the object by a phase-shifting interferometry, and the phase-shifting interferometry is at least a three-step phase-shifting.
6. A method for reconstructing a surface of an object, comprising steps of:
modulating a light beam by a spatial light modulator (SLM), and the light beam being projected to form a pattern, wherein the pattern has a transmittance distribution defined by a sinusoidal wave equation such that the pattern is formed to become a fringe pattern with a phase distribution, wherein a first period of the phase distribution has an impulse variation in a first degree, and a second period of the phase distribution has an impulse variation in a second degree, wherein a position where the impulse variation in the first degree occurs within the first period is a first relative position, and a position wherein the impulse variation in the second degree occurs within the second period is a second relative position, wherein the first degree and the second degree have difference, or the first relative position and the second relative position have difference;
guiding the light beam to the object, such that a scan pattern is formed on the object;
reading the scan pattern; and
calculating a surface profile of the object according to the scan pattern.
7. The method of claim 6 , wherein the pattern is formed by a plurality of pixels aligned along a direction of a straight line, and the sinusoidal wave equation satisfies:
t
=
A
+
B
cos
[
2
π
x
T
0
+
2
π
m
M
δ
(
x
-
n
T
0
-
l
)
]
,
wherein t is the transmittance distribution of the fringe pattern, A and B are real numbers, x is a pixel order on the direction of the straight line, T 0 is a fringe period of the fringe pattern, and x. M, m, n and 1 are positive natural numbers, wherein m<M, 1<T 0 , and the positions where the first relative position and the second relative position occur are defined by δ(x−nT 0 −l).
8. The method of claim 6 , wherein the first degree and the second degree are different, and the first relative position and the second relative position are the same.
9. The method of claim 6 , wherein the first degree and the second degree are the same, and the first relative position and the second relative position are different.
10. The method of claim 6 , wherein the first degree and the second degree are different, and the first relative position and the second relative position are different.
11. An optical system for reconstructing a surface of an object, comprising:
a spatial light modulator (SLM), for modulating a light beam, and the light beam being projected to form a pattern, wherein the pattern has a transmittance distribution defined by a sinusoidal wave equation such that the pattern is formed to become a fringe pattern with a phase distribution, wherein a first period of the phase distribution has an impulse variation in a first degree, and a second period of the phase distribution has an impulse variation in a second degree, wherein a position where the impulse variation in the first degree occurs within the first period is a first relative position, and a position wherein the impulse variation in the second degree occurs within the second period is a second relative position, wherein the first degree and the second degree have difference, or the first relative position and the second relative position have difference;
an image receiving device; and
a pair of light guiding lenses, respectively optical coupling to the spatial light modulator and the image receiving device.
12. The optical system of claim 11 , wherein the pattern is formed by a plurality of pixels aligned along a direction of a straight line, and the sinusoidal wave equation satisfies:
t
=
A
+
B
cos
[
2
π
x
T
0
+
2
π
m
M
δ
(
x
-
n
T
0
-
l
)
]
,
wherein t is the transmittance distribution of the fringe pattern, A and B are real numbers, x is a pixel order on the direction of the straight line, To is a fringe period of the fringe pattern, and x. M, m, n and 1 are positive natural numbers, wherein m<M, 1<T 0 , and the positions where the first relative position and the second relative position occur are defined by δ(x−nT 0 −l).Cited by (0)
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